Using X-ray technology in the preservation of cultural assets

Historical objects stand as testimony to our cultural past. They speak of personalities, of nations – indeed, of humanity. The most important task in saving cultural assets is preserving this heritage. To do so, these pieces of art and everyday items must be carefully examined and researched.

Every culture has its traditions, its rituals and its artistic epochs. Just from the way objects are designed, historians can read a lot about the people who originally used them. Frequently, the material composition is characteristic of a specific time period or region. Thus, accurate material analysis can make it possible to distinguish originals from counterfeits or to detect parts that were added later.

So as not to damage these often delicate and valuable objects, the examination method must be as gentle as possible. Non-destructive X-ray fluorescence analysis is therefore ideal for use on cultural assets.

Since it was designed as a flexible handheld instrument, Fischer's XAN 500 X-ray fluorescence instrument is convenient to use outside a laboratory. Despite its small size, it is nonetheless equipped with the full-fledged WinFTM® software. Plus, fundamental parameter analysis allows unknown alloys to be inspected for their components without prior calibration.

Fig.1: The handheld XAN 500 makes it possible to measure bulky and odd-shaped parts right where they stand, for example in museums or at excavation sites. (Photo: Esther Hoyer)

The XAN 500 was tested at the GRASSI Museum of Applied Arts in Leipzig to examine an eagle lectern. The piece presumably dates from the 12th or 13th century and was made in Italy. Because the lectern consists of several parts bearing different stylistic elements, the restorer suspected that not all these elements were original.

Fig. 2: Measuring on a lectern with a single column: All parts are made of brass. The small differences in the composition are probably due to inconsistencies in production.

Alloy analysis with the XAN 500 showed that the piece was made of tombak, a high-quality brass with a high copper content. All parts showed comparable concentrations of copper, zinc and lead – a strong indication that all pars were original. In addition, traces of nickel, tin, iron and antimony were found in the alloy.

X-ray fluorescence analysis based on the fundamental parameter method makes it possible to detect all the different components of an alloy. In this way, conservators can choose the correct materials to restore cultural assets as faithfully as possible, in order to preserve them for future generations.